The present invention relates to an electronic pattern generator for line-by-line recording of characters from stored video-data. The characters to be recorded are displayed on the screen of a cathode ray tube and then exposed on a recording medium mounted on a carrier, which is displacable in a plane parallel to the plane of the screen. The pattern generator includes a control circuit which may be controlled by commands for transforming the video data into a first video signal, for generating deflection signals required for the display of characters on the screen of the cathode ray tube and for obtaining displacement signals for the carrier.
Such characters include writing, special signs, symbols, rastered half-tone images, and graphic displays such as signatures, diagrams or line drawings. The characters required for a pattern are stored in the form of video data for the cathode ray tube in a digital memory.
The text to be set is first transformed by a composition calculator into recordable data, which constitute the commands for the pattern which is to appear on the pattern generator.
During operation the recording data recall the video data to be recorded from the digital memory sequentially, for generating the required characters. Each character called for is recorded by an appropriate brightness control of the electron beam on the screen of the cathode ray tube, the characters being arranged to yield line-by-line words, sentences, or other representations.
The image on the screen is exposed by means of appropriate optics on a film or on photo-sensitive paper. The developed film then represents already the master for offset printing. The pattern developed on the previously exposed photo-sensitive paper is denoted as the galley proof. Prior to the final generation of the printing master the text must be examined for correct layout, and if necessary, corrected and appropriately edited.
Video data terminals (VDT) may be used for correcting the texts, by means of which, in cooperation with a composition calculator, it is possible to process the recorded data. Data and complete data blocks are recalled from the composition calculator, displayed on an editing screen, corrected by means of a terminal, and again written into the composition calculator.
Although it is possible to correct the text by means of the video data terminal, it is not possible to judge the composition and make-up with respect to the type fonts, type sizes or arrangement of columns of text, heading and/or images, as the text is only displayed line-by-line or block-by-block on the screen of the video data terminal in a font of unitary fashion. In order to control the lay-out and page make-up of the composition it is therefore necessary to obtain a galley proof. This galley proof is read by the correction editor, and is again returned to the pattern generator with new correcting orders, so that the data can be appropriately corrected by means of the video data terminal.
This method is time-consuming and uneconomical. As a relatively expensive material is used for the galley proof, additional costs are generated. Development of the galley proof also requires a pre-determined time, until it is developed and ready for editing purpose. Additional time is lost by transporting the galley proof from the printing room to the editing room and back.
Recently there have become known so-called soft copy terminals, which make possible the processing of typographically difficult composing operations, such as, for example tables, advertisements, full page make-up and the like.
This soft copy terminals includes a separate character generator controlled by the pattern generator, which generates on the screen also only an unitary font. By this means normal type-faces and italics, or various other styles, such as "Antigua" or "Tempora", are reduced to an uniform matrix or style in the known soft copy terminals.
Such a standardization of fonts is a critical disadvantage, since the effect of a layout or make-up from an editing point of view can only be judged with a sufficient degree of certainty from an original character.
The resulting matrix font may contain within a predetermined region different typesizes but this region does not include by any means all typesizes occurring in practice, so that these must be equalized to a realizable size or scale.
As a result of this equalization, a distorted character occurs, and the composition is shown on the screen only in an approximate manner, compared to the galley proof, or to the final product.
The display on the screen of a known soft copy terminal does not convey, however, a true total impression required for print-setting purposes, which is considered a further disadvantage.
Video data terminals of the prior art used for correcting a text are described, for example, in "The Seybold Report", Vol. 6. No. 4, p. 4-16, No. 10, p. 10-7, No. 9, p. 9-8, and No. 10, pp. 10-4 through 10-6. A combination of a video data terminal and a known soft copy terminal is described, for example, in "The Seybold Report", Vol. 6, No. 4, p. 4-15.